How Many Hacks in an LED Display?

There are so many nice hacks in [Joekutz]’s retro LED display project that it’s hard to know where to start. There’s his DIY LED display controlled by an Arduino UNO. To have some text or picture for the display, he’s wired the output of a Bluetooth speaker directly to the Arduino, and sends it speaker tones that encode the text to draw. And as if that wasn’t enough, he’s hacked a quartz driver board from an analog clock to use the display as a clock as well.

Let’s start with the LED matrix display, perhaps the best excuse for trying your hand at shift registers. This display uses two such 8-bit shift registers daisy chained together feeding two 8-bit Darlington arrays. The display has ten rows of sixteen columns, and you guessed it, the columns are controlled by the sixteen shift registers. Two Arduino pins tell the shift registers which column to turn on. The rows are turned on and off using ten transistors controlled by ten more Arduino pins. Scanning at 80 frames per second he gets a nice, flickerless display.

To make both the LED matrix circuit board and the control board, [Joekutz] carved out isolation paths in copper clad boards using his homemade CNC mill. Be sure to check out the first video below to see his misadventures with it that ultimately led to his gorgeous boards.

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These Engineering Ed Projects are Our Kind of Hacks

Highly polished all-in-one gear for teaching STEM is one way to approach the problem. But for some, they can be intimidating and the up-front expenditure can be a barrier to just trying something before you’re certain you want to commit. [Miranda] is taking a different approach with the aim of making engineering education possible with junk you have around the house. The point is to play around with engineering concepts with having to worry about doing it exactly right, or with exactly the right materials. You know… hacking!

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Tightwad Hacks Label Printer, Beats Manufacturer at Own Game

Sometimes we hack for the thrill of making something new, and sometimes we hack to push back the dark veil of ignorance to shed fresh light on a problem. And sometimes, like when turning a used label printer into a point-of-sale receipt printer, we hack because we’re cheapskates.

We say that with the utmost respect and affection — there’s nothing to be ashamed of when your motive is strictly pecuniary. In [Dan Herlihy]’s case, hacking a cheap Brother label printer to use thermal paper meant saving $300 on a dedicated receipt printer. But it also meant beating Brother at their “Razor and Blades” business model that keeps you buying their expensive proprietary labels. A pattern of holes in the plastic label roll tells the printer what size labels are loaded, so [Dan] defeated that by breaking off a piece of the plastic and gluing it on the sensor. To convince the printer that plain thermal paper is label stock, he printed up a small strip of paper with the same pattern of black registration stripes that appear on the back of the labels. Pretty clever stuff, and it lets him print high-resolution receipts for his electronics shop on the seriously cheap.

[Dan]’s hack is simple, but may suffer from wear on the paper encoder strip. Perhaps this Brother hack using the gears as encoders will provide some inspiration for long-term fix.

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The Complex Issue Of Hackspace Donations

More than one member of the Hackaday team has significant involvement in a hackspace, as member, director, or even founder. We talk about hackspaces quite rarely on these pages though, not because we don’t have anything to say on the matter but because even when we write in general terms our fellow members invariably think it’s all about them rather than the hackspace world at large.

For once I’m going to break the silence, and not only talk about hackspaces, but talk about my own hackspace in specific terms. Because, fellow Oxford Hackspace members, this isn’t about you personally though I’m using our home to illustrate a point. The topic is a thorny issue that must affect all spaces, that of donations of physical items. People want to help their hackspace, they have a pile of what they consider to be good stuff, and when they’re having a clear-out they make a donation. But, as we all know, “one man’s trash is another man’s treasure” and vice-versa. Continue reading “The Complex Issue Of Hackspace Donations”

Press Button, Receive Hackspace WiFi Code

When you are running a hackspace, network security presents a particular problem. All your users will expect a wireless network, but given the people your space will attract, some of them are inevitably going to be curious enough to push at its edges. Simply plugging in a home WiFi router isn’t going to cut it.

At Santa Barbara Hackerspace they use Unifi access points on their wireless network, and their guest network has a system of single-use codes to grant a user 24-hour access. The system has the ability to print a full sheet of codes that can be cut individually, but it’s inconvenient and messy. So the enterprising hackspace members have used a Raspberry Pi and a receipt printer to deliver a single code on-demand at the press of a button.

The hardware is simple enough, just a pull-up and a button to a GPIO on the Pi. Meanwhile the software side of the equation has a component on both client and server. At the server end is a Python script that accesses the Unifi MongoDB database and extracts a single code, while at the client end is another Python script that reacts to a button press by calling the server script and printing the result.  It’s a simple arrangement that was put together in an evening, but it’s an effective solution to their one-time WiFi access needs.

It’s a temptation as a hackspace to view all of your problems as solvable in one go with the One Piece Of Software To Rule Them All, and as a result some spaces spend a lot of time trying to hack another space’s effort to fit their needs or even to write their own. But in reality it is the small things like this one that make things work for members, and in a hackspace that’s important.

Does your space have any quick and simple projects that have automated a hackspace process? Let us know in the comments.

Thanks [Swiss] for the tip.

Metalworking Hacks Add Functionality to Snap-On Tool Chest

Problem: you’re a student mechanic and you’ve already poured a ton of money into a Snap-On roller cabinet loaded with the tools of the trade, but you still need sensible storage for your cordless tools. Solution: a DIY version of Snap-On’s PowerCab cordless tool station at a fraction of the cost.

rnqvgsoMechanics seem to have a love-hate relationship with Snap-On tools. Some love the brand, others hate it, but the majority seem to hate that they love the tools. It sounds like [GenTQ] reached her limit on brand loyalty when even her 50% student discount wasn’t enough to entice her to add Snap-On’s admittedly very cool KRL1099 cabinet for cordless drivers and chargers. So it was off to Harbor Freight for their seven-drawer side cabinet for less than $200. The cabinet was gutted of drawers, a frame for the new slide-out was welded up, and sheet steel was fabricated into organizer shelves and a new drawer front. A power strip and drag-chain were added to feed the chargers, and the new drawer went off to the powder coater for a matching paint job.

It may not have the Snap-On badge, and purists may cringe at the mixed-marriage with Horror Fright, but we like the results just fine. And she saved something like $1200 in the process. We think Harbor Freight gets a bad rap, deservedly so for some tools, but there are hidden gems amid the dross just ripe for the hacking, as [GenTQ] ably shows.

[via r/DIY]

MIDI DAC for Vintage Synth Hacks

A lot of classic synthesizers rely on analog control voltages to vary parameters; this is a problem for the modern musician who may want to integrate such hardware with a MIDI setup. For just this problem, [little-scale] has built a MIDI-controllable DAC for generating control voltages.

It’s a simple enough build – a Teensy 2 is used to speak USB MIDI to a laptop. This allows the DAC to be used with just about any modern MIDI capable software. The Teensy then controls a Microchip MCP4922 over SPI to generate the requisite control voltages. [little-scale]’s video covers the basic assembly of the hardware on a breadboard, and goes on to demonstrate its use with a performance using the MIDI DAC to control a Moog Mother 32 synth. [little-scale] has also made the code available, making it easy to spin up your own.

We can see this project being indispensable to electronic musicians working with banks of modular synths, making it much easier to tie them in with automation in their DAW of choice. This isn’t the first MIDI interfacing hack we’ve seen either – check out this setup to interface an iPad to guitar pedals.

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